1. Field of the Invention
The invention relates to a liquid crystal device (LCD), and more particularly to a liquid crystal device having a ventilated thin film with high reflective material.
2. Description of the Prior Art
Following the development of science and technology, the volume of the display device is gradually reduced, and the weight becomes relatively lighter. Although the conventional display devices with cold cathode fluorescent tubes have their merits, they are bulky and power consuming. For these reasons, the plane display device, such as liquid crystal device (LCD), plasma display device, and electrically actuating display device etc. has gradually become the main stream of the display device. Among them, LCD has become very popular in the market due to its advantages of having relatively low operating voltage, no radioactivity, light in weight, and small in volume etc. It is necessary for a backlight module to provide a light source since the liquid crystal elements themselves in the LCD structure are not luminous.
One can classify the backlight module into two types, a side light type backlight module and a direct type backlight module, depending on the location of the light source disposed in the liquid crystal device. The light source of the side light type backlight module is disposed on a side plate of the liquid crystal device. A light-guiding plate is needed to guide the light beam illuminated from a light source through a diffuser and a reflector to uniformly illuminate on the display panel of the LCD.
On the contrary, the light beam of the direct type backlight module, through a diffuser and a reflected sheet, directly and uniformly illuminate on the liquid crystal (LC) panel without the need of a light guiding plate. Therefore, this type of backlight module can be used in a relatively larger size of LCD since it is relatively higher in light transmissibility.
The heat source inside the backlight module mainly comes from the cold cathode fluorescent tubes installed therein, and the luminous efficiency of the cold cathode fluorescent tubes is apt to be affected by the temperature change. FIG. 1 is a conventional backlight module. As shown in FIG. 1, since the interior of a backlight module 10 having cold cathode fluorescent tubes 11 contained therein is a closed space, the air heated by the cold cathode fluorescent tubes 11 inside the closed space is unable to generate convection with respect to the outside environment causing the non-uniformity of the interior temperature. The heat generated inside the backlight module needs to transfer to the exterior parts, then, irradiate from the surface of the exterior parts toward the outside environment. Consequently, the heat dissipation of this kind of conventional backlight module 10 is not effective and the temperature inside the backlight module is not apt to lower. This will not only affect the luminous efficiency of the cold cathode fluorescent tubes but also affect the quality of displaying picture of the LCD.
As the trend of the size of the LCD is getting bigger and bigger nowadays, the number of the cold cathode fluorescent tubes and the temperature of the backlight module are getting higher. How to lower the temperature of the backlight module to avoid the lowering luminous efficiency of the light source is an important issue of study on the backlight module.